The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Acute heart failure occurs frequently in chronic heart failure, especially in Class III and IV patients, and is extraordinarily prevalent. It is characterized by peripheral edema, lung congestion, and often both. Patients are admitted to the hospital, and typically spend five inpatient days “drying out”, through extended diuresis and inotropic support. Without hospitalization, patients risk death from acute heart failure and concomitant respiratory failure creating hypoxia due to pulmonary edema.
Decompensation from heart failure can eventuate into cardiohepatic syndrome, which is characterized by failure of the heart and liver, and cardiorenal syndrome, which is characterized by simultaneous heart and kidney failure. The primarily failing organ may be the heart or kidney, and it is often this failing organ that precipitates failure of the other. Treating acute cardiac decompensation is through potent diuresis by continuous or bolus loop diuretic infusion, vasodilators, and inotropic support. Potent diuretics stimulate the kidneys to excrete fluid to eliminate excess intravascular and extravascular fluid, but often eventuate in renal failure.
Some have contemplated catheter systems to increase renal perfusion and function. For example, Patel (U.S. Pat. No. 7,766,961) discloses a drain catheter for reducing the venous pressure of the renal system. The catheter is positioned in the renal vein, and an expandable member is inflated within the renal vein to occlude the renal vein from the venous system. An external reversible roller pump is used to extract blood from a distal tip of the catheter into a drain line. The extracted blood is then inserted back into the venous system through a return line in the femoral vein. While the drain catheter of Patel increases renal perfusion, the discharge of extracted blood in the femoral vein may cause unfavorable pressure changes in the venous system upstream of the renal veins.
Others have contemplated systems for controlling pressure in the venous system. Some examples of these systems include Kieval (U.S. Pat. Pub. 2013/0199806), Kandarpa (U.S. Pat. Pub. 2012/0232457), Gelfand (U.S. Pat. Pub. 2004/0163655), Allers (U.S. Pat. Pub. 2004/0210236) and Celermajer (U.S. Pat. Pub. 2011/0190874). However, such systems are typically overly complicated.
Others have contemplated blood pumps that can be positioned within a patient. For example, Rau (Canadian Pat. 2,250,993) discloses a blood pump that is connected to a catheter. The blood pump has a blocking device that separates a suction side from the delivery side. However, the blood pump is designed to be positioned at a site upstream of an organ within a blood vessel, such as an artery.
These and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Thus, there is still a need for a device to mechanically improve the arterial-venous pressure gradient across an organ to thereby improve global organ function.